It is known that ammunition magazines are used with firearms. The typical magazine includes a magazine casing that defines a housing or body in which the ammunition is stored. The typical magazine also includes a follower that is spring-urged from the floor of the magazine toward the feed end of the magazine. The feed end of the magazine is inserted in the magazine well of the firearm and interacts with the bolt assembly of the firearm. During loading of the ammunition into the magazine, the ammunition cartridge pushes the follower down towards the floor and compresses the spring, which is acting against the follower. In operation, when one cartridge of ammunition is stripped out of the magazine by the firearm's bolt, the compressed spring pushes or urges the follower and remaining ammunition up toward the feed end, and the next cartridge is then put in position to be removed by the bolt for firing.
There remains a need, however, for an improved magazine for an AR-style firearm, that reduces splay or wobble of the follower and that may be usable with ammunition such as .40 caliber ammunition and in a single stack configuration.